1. Field of the Invention
The present invention is relates to a protein crystallization apparatus and a protein crystallizing method.
2. Description of the Related Art
The technology for growing protein crystal is important in protein structural analysis. The structure of the protein crystal can be identified by using an analysis method like X-ray diffraction. The identification of the structure of the protein crystal is indispensable especially for the development of medicine including the protein crystal.
As the methods of crystallizing protein, a method of crystallizing the protein under a still condition is known (still condition batch method, a liquid-liquid (free boundary) diffusion method, a small amount dialysis method and so on). In the method of crystallizing the protein by decreasing the solubility of the protein, protein solution and buffer solution containing precipitant are enclosed in the same vessel. When the precipitant diffuses into the protein solution, the solubility of the protein decreases and the protein is crystallized.
However, in the conventional method of crystallizing the protein by decreasing the solubility of the protein under the still condition, it is difficult to grow the protein crystal isotropically.
Moreover, the crystallization of the protein is slow in the growth speed of the crystal. For this reason, it takes a long time to grow the protein crystal. This is one factor to obstruct the improvement in efficiency of the protein structural analysis.
In conjunction with the above description, a protein crystallizing method is known in Japanese Laid Open Patent Application (JP-A-Heisei 6-321700). In the conventional protein crystallizing method, protein gel 105 containing protein, precipitant gel 106 containing precipitant, and buffer solution gel 107 containing only buffer solution are put into a vessel 101, as shown in FIG. 1. In this way, gel is used to supply necessary material for the growth of a protein crystal in the conventional protein crystallizing method. It is described in the above reference that the use of the gels is a purpose to make convection small as much as possible. In the vessel 101, a sandwich structure is formed in which the precipitant gel 106, the buffer solution gel 107, the protein gel 105, the buffer solution gel 107 and the precipitant gel 106 are stacked in order. The vessel 101 is reversed up and down while the protein crystal grows. The precipitant contained in the precipitant gel 106 passes the buffer solution gel 107 and diffuses into the protein gel 105 in the conventional protein crystallizing method. The present invention does not need gelatinization and is fundamentally different technology from the conventional protein crystallizing method.
Therefore, an object of the present invention is to provide a protein crystallizing technique in which it is possible to grow a protein crystal more isotropically.
Another object of the present invention is to provide a protein crystallizing technology in which it is possible to promote the growth of the protein crystal.
In a protein crystallization apparatus includes a vessel supporting section and a rotating unit. A vessel is detachably fixed to the vessel supporting section. The rotating unit rotates the vessel supporting section around first and second rotation axes. The vessel contains protein solution and a protein crystal grows while the vessel supporting section is rotated.
The rotating unit may include a first rotating unit which rotates the vessel around the first rotation axis, and a second rotating unit which rotates the first rotating unit around the second rotation axis. In this case, the first rotating unit may include an inner frame which supports the vessel supporting section; and a first motor which rotates the inner frame. Also, the second rotating unit may include an outer frame to which the first rotating unit is mounted; and a second motor which rotates the first rotating unit.
The rotating unit rotates the vessel supporting section to meet the following differential equations (1),                                           φ            .                    =                      A                          |                              sin                ⁢                                  xe2x80x83                                ⁢                φ                            |                                      ⁢                  
                ⁢                              θ            .                    =                      B                          |                              sin                ⁢                                  xe2x80x83                                ⁢                φ                            |                                                          (        1        )            
where xcfx86 is an angle between a predetermined direction perpendicular to the first rotation axis and the outer frame, and xcex8 is an angle between a predetermined direction perpendicular to the second rotation axis and the inner frame, and A and B are selected such that 2 m/n (m and n are positive integers) is not an integer to minimum n and m meeting a relation of A:B=n:m.
Also, it is desirable that the rotating unit rotates the vessel supporting section such that gravity is applied to the vessel isotropically.
Also, the vessel may include a vessel section having an opening; a sealing section which seals the opening of the vessel section; an absorption member which is provided in the vessel section and in which precipitant solution is absorbed; and a button provided apart from the absorption member in the vessel section to hold the protein solution. Precipitant evaporates from the absorption member and diffuses in an inside of the vessel section. The precipitant is absorbed by the protein solution and the protein crystal is precipitated.
In another aspect of the present invention, a protein crystallizing method is achieved by (a) providing a vessel to a vessel supporting section; by (b) rotating the vessel supporting section around first and second rotation axes; and by (c) growing a protein crystal while the vessel supporting section is rotated, wherein the vessel contains protein solution.
The (b) rotating step may be achieved by rotating the vessel around the first rotation axis; and by rotating the first rotating unit around the second rotation axis.
Also, the (b) rotating step may be achieved by rotating the vessel supporting section to meet the following differential equations (1),                                           φ            .                    =                      A                          |                              sin                ⁢                                  xe2x80x83                                ⁢                φ                            |                                      ⁢                  
                ⁢                              θ            .                    =                      B                          |                              sin                ⁢                                  xe2x80x83                                ⁢                φ                            |                                                          (        1        )            
where xcfx86 is a rotation angle with respect to the first rotation axis and xcex8 is an a rotation angle with respect to the second rotation axis, and A and B are selected such that 2 m/n (m and n are positive integers) is not an integer to minimum n and m meeting a relation of A:B=n:m.
Also, the (b) rotating step may be achieved by rotating the vessel supporting section such that gravity is applied to the vessel isotropically.
Also, the protein crystallization method may further include: providing the vessel. The vessel includes a vessel section having an opening; a sealing section which seals the opening of the vessel section; an absorption member which is provided in the vessel section and in which precipitant solution is absorbed; and a button provided apart from the absorption member in the vessel section to hold the protein solution. Precipitant evaporates from the absorption member and diffuses in an inside of the vessel section. The (d) growing step may be achieved by evaporating the precipitant from the absorption member; by absorbing the precipitant by the protein solution; and by precipitating the protein crystal.